Well, assuming either extant megafauna or the huge buffalo herds, the riding raptors (or their Moa descendants) could still pay off (assuming you could train them for riding, of course). Smart, fast and equipped with fearsome natural weapons of their own, they'd naturally take down that kind of prey in small packs of 5-10 creatures. Now add in the human element of sophisticated tactics, ranged weapons (bow, axe and spear) and riding techniques analogous to what we see in horsemen and the hunting party becomes (potentially) more efficient than a RW one. Get in close, use your raptors to cut a target from the herd, use ranged weapons to wound it, and then take it down- either with your own weapons or letting the raptors take it down themselves. Getting that meat supply wouldn't be that big an issue.
Something as big as a true Moa or midsize raptor would be the equivalent of a tank, and a tribe might only be able to handle a small number- 2-5 beasts total. But they would probably develop tank/armored knight style tactics to go along with such critters if they had them- a couple of riders with ample ammo supported by "infantry."
As for the smaller raptors or carnivorous flightless birds, using packs of them to hunt with would be no more a problem than using hunting dogs. That's just a matter of flavor.
Remember that while reptiles of all kinds prefer live prey, most don't turn their noses up at carrion. Some scientists propose that some of the raptors and carnivores may have even preferred it- its an easy meal, after all, that entails no risk of injury...and reptiles have fairly robust digestive systems.
True, they don't... but dogs aren't enormous cold-blooded killers who could gain the knowledge to open doors

. Really, I just would fear the heat-loss/over-heating of a heavy pack dinosaur loaded with hundreds of pounds of cargo and little internal method to get that sweet spot of homeostasis.
Friends don't let friends write setting material without backup

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I'm still stuck on the fire-based warrior style. Fire-based cultures for humanity make for some bad mamajama warriors and mystics also. That sweet guano economy could breed Hellenic-style tribal sharings (i.e. we trade you fledgling warmages for large sources of guano and your skilled trappings).
Ugh, sweet guano.
Loonook's excellent expansion on my Moa idea reminded me of something.
Again with the love... Danny, you need to slow down or people will start talking

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I read about a really cool take on a nomadic society in a short story in Fantasy & Sci-Fi magazine some years ago. The society was focused on beekeeping, and they maintained a variety of hives, each in large, specialized wagons. They traveled the lands in order for the hives to have access to a wide variety of flowering plants, which in turn affected the quality and flavors of the honey they produced...and, of course, to help pollinate crops. Beyond their pollination biz, they sold some of their exotic honeys at fairly decent prices.
Part of the tribal leadership's role was, of course, knowing where to go and when. If you miss the blooms, you miss the pollens, and if you miss the pollens, you don't get any honey or business from the farmers. Get the right mix and your honeys are as complex and subtle as wines, and will sell at exorbitant prices. Get it wrong and your honey may be merely pedestrian. Get it wrong often enough and it may ruin demand for your product in the future, and may even force you to abandon certain routes as unprofitable.
Agreed on that story. Plenty of possible trade items from a seminomadic/nomadic society trading with demihumans. The tribes, with their nice supply of rich guano (really, I worry we're creating the Poo People of this world), various exotic meats, rare materials, wild herbs, honey, skilled trade goods, and breeding stock of their animals would be useful.
Irish Travelers are well renowned for their dog breeding, and with the right rituals and a long history of breeding... you could produce some pretty powerful beasts. Magebred animals a la Eberron which could easily be raised by a nomadic culture could include dogs, raptors (of the scaly and feathered variety), pack animals, and various creatures which can fit in small areas and benefit from movement across the land. Silks which are weaved from the spiderfolk in the Insertnamehere Mountains (or worms kept in a large safe wagon), fine honey as listed by DA (a GREAT supplemental income to lands which can't support witchfolk to help them with plant growth and special farming magic/pollination), trained animals of all sorts, and amber and exotic woods from farflung regions. Skilled trades would of course bring their fletchings, various handicrafts created from their travels, and talents which are easy to hone on the roads.
Depending on if the humans think in long or short times... you could easily have humans who are fine winemakers... who hide their maturing deliciousness in secret caves before they are casked and brought to market. Humans may also have a great knowledge of lore which is wanted by various wisemen from all of the nations... and that could prove useful to rogues. A culture moving between a dozen lands can collect the good and the bad.
Black Lotus extract is powerful... but pretty mundane when you travel the wide world.
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I think that the Manni from the Dark Tower series by Stephen King could also be an interesting subsect of human culture... imagine planes drifting nomads who are similar to the Amish. Could prove interesting for a 'lost tribe' dynamic.
Slainte,
-Loonook.